Starting mechanism for internal-combustion engines



F. CONRAD.

STARTING MECHANISM FOR INTERNAL co'magsnou ENGINES? APPLICATION FILED DEC.26, I913.v 1,413,829. I Patented Apr. 25, 1922.

WlT SSES: INVENTOR I I I I p f .b f Q4. j 2 ATTORNEY 4 E.CONRAD. STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED DEC.26| 1913- 1,413,829. I atented Apr. 25, 1922.

2 SHEETS-SHEET 2.

ATTORNEY movement between the FRANK CONRAD, PITTSBURGH PENNSYLVANIA, ASSIGNOR 'I'O WESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPQRATION OF PENNSYLVANIA.

STARTING MECHANISM FOR INTERNAL COMBUSTION ENGINES.

Specification 01' Letters Patent. Patented Apr, 25 1922,

Application filed December 26, 1913. Serial No. 808,783. I

To all whom it may concern:

Be it known that I, FRANK CONRAD, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Starting Mechanism for Internal-Combustion Engines, of which the following is a specification.

My invention relates to starting mecha-' nisms for internal combustion engines and particularly to such mechanisms as embody electric motors. Q I

My invention has for one of 1tsobjects to provide a simple and efl'eotive -means whereby a startingmotor may be automatically connectedto and disconnected fromthe shaft of an internal combustion engine.

A second object of. my invention is to provide a starting mechanism that operates without excessive shocks incident to the automatic engagment of a motor-driven pinionand the fly wheel gear.

As heretofore constructed, mechanisms of this character must, ordinarily, be connectedto the engine. shaft by manually operatect' means or, if automatic means be employed, additional structure-is necessary which adds materially to the cost of manufacture and to the weight and complexity of thelstarting device.

My invention comprises a motor having an armature shaft which is operatively con-' nectedto a screw threaded shaft to zcoact with 'a' correspondingly threaded gear wheel"- to shift the latter into and out of mesh with a gear wheel'on the engine shaft. A frictionclutch connects the motor shaft to the screw-threaded shaft. Magnetic means are.

emplo ed to supplement the inertia of the three ed gear wheel to' produce. relative gear wheel and the threaded shaft.

In the accompanying drawings, Fig. 1 is a side view, partially in elevation and partiall in section, on line 1-1 of Fig 3, of an e ectric motor with my invention apa pliedthereto. Fig. 2 is a sectional view illus-.

tratin an electromagne t for holding the three ed gear wheel, the electrical connections bein shown diagrammatically. Fig. 3 is an end view of a portion of an enginehaving thereto.

An electric motor 1 has an armature shaft 2 that isprovided with a pinion i A gear the starting mechanism attached wheel 4, which meshes with the pinion 3, is

mounted upon a shaft 5 for frictional engagement' with two flanged collar members 6 and 7 that are'mounted upon the shaft 5. The collar members 6 and 7 are provided, upon their adjacent faces, with friction material 25- to engage the gear wheel 4. The collar member 7 is slidably mounted upon the shaft 5- and is normally pressed against-the gear wheel 4 by a spring 8. The

, collar member 6 is screw-threadedupon the shaft 5 to provide .a means for adjustin the degreeof tension of the spring 8 an thereby. controlling the amount of friction for preventing relative movement of the' several parts. The clutch is so adjusted that it' will transmit, without yielding, the

torque necessary to. actuate the engine'under normal conditions, but will yield temporarily in case of sudden application of excessive torque such as may occur upon the automatic engagement of coacting gear wheels of the starter and the engine. -The' shaft 5 is provided with a threaded portion correspondingly threaded to coact with the .shaft. "The pinion 10 is provided with a collar member 11 having a cylindrical shoulder portion 12 to be engaged by spring clips 13.that are mounted between the collar member 6 andv the spring 8. The collar '9 upon which is mounteda pinion 10 that is member 11 is provided upon'its periphery with four oppositely disposed pole pieces 14. .An'electromagnet 15, Fig. 2, comprisin a core member 16 that spans a pair of a jacent poleipieces 14 anda c0il 17 that is 1 I in series with the, p with the pole pieces 14; to hold the pinion 10' against rotative movement and thereby I produce an axial movement of the pinion 10 on the shaft 5 when thelatter rotates. The clips 13 tend to rotate the pinion 10 with the shaft-5 but the magnet 15 exerts the stronger'force'when the parts are stationary, as will be later described. A housing '18 moral-mature, coacts partially, encloses the mechanism above described and provides bearings for theshaft5.

- Referring particularly to Fig. 3, a gas ,engine 19, only a portion of which isshown,

comprises a crank case 20, a shaft 21, and a fly wheel 22 that is provided with gear teeth 23 to coact with the pinion 10. A bracket 24, which is attached to the under side of the crank case 20, sup-ports the motor 1 and its connected mechanism.

When the circuit of the motor 1 is closed through any suitable electrical connections, as, for example, thecircuit of Fig. 2, the coil 17 is energized to cause the core member 16 to attract that pair of pole pieces 14 which are nearest the same to prevent the rotation of the .pinion 10. The armature shaft 2 will rotate the shaft 5 through the pinion 3 and gear wheel'4. The pinion 10, the rotation of which isopposed by the magnet 15 and by its own inertia, 'will be advanced outwardly along-the shaft 5 by means. of the screw threads until it meshes with the fly wheel gear teeth 23 and engages a collar member 26 that acts as a stop to limit-its endwise movement.

The teeth of the pinion 10 are rounde or'beveled at their outer ends as'indicat'ed at 27 in order to facilitate the meshing ;of the respective gear teeth; It is only necessary that the magnet hold the pinion for a very brief interval because of the small movement required to bring the gear teeth into engagement. Because of the high speed attained by the motor at the oint of meshing the pinion 10 with the y wheel gear teeth 23 and of the relatively'high inertia of the engine, a severe shock would occur when the pinion 10 reaches the collar 26 if the driving connections were suddenly established through a rigid mechanism. The

frictional connection of the gear wheel 4 with the shaft 5 allows a temporary relative movement between these parts so that a shock is avoided. During the temporary slipping of the fr ction clutch, sufficient torque is trans mitted to overcome the inertia of the engine.

' This torque is greater than that required under normal conditions. As soon as the engine has acquired such speed that the torque transmitted by the clutch is within a' predetermined value, relative movement between the clutch arts ceases. The clutch may be so adjuste that the values of the torques transmitted under the conditionsabove described are well within the limits re lured to operate the engine.

hen the engine starts under its own power, the fly wheel rotates at a speed sufficiently high to cause pinion 10 to overrun the shaft 5- and to be disengaged from the fly wheel gear teeth23 as it travels inwardly along the shaft. When the pinion approaches the endof its path of, movement in this direction, "the clips 13 engage the shoulder portion 12 to carry the pinion 10 with the shaft 5 and thereby prevent the will ordinarily open the motor circuit almost immediately after the engine starts, a safety device is essential in order to provide for any delay or neglect on the part of the operator.

In case of backfire of the engine, the friction clutch yields and damage to the motor or associatedpart is prevented.

It will be noted that I have provided a mechanism which is entirely automatic in its operation to, operativelv connect a starting motor to the shaft of an internal oombustion engine and to disconnect the same when the engine 'startsunder 1ts own power.

I claim asmy inventlon:

1. In a starting mechanism, the combination with a gear wheel,1and a pinion having I pole pieces, of a shaft having a screwthreaded connection wlth'said pinion, and a magnet coacting with said pole pieces.

2. In a-starting mechanism, the combmation with a gear wheel, anda pinion coacting therewith, of means for h1ft1ng said pinion into and out of mesh w1th said gear wheel, said means comprislng a spirally threaded shaft and electromagnetic means for opposing rotationof said pinlon.

3. In a starting mechanism, the combination with an engine shaft, and a gear wheel connected thereto, of amotorhavin'ga shaft, a spirally threaded shaft operatively connected to said motor shaft, a pinion on said threaded shaft for coacting therewith, and a magnet for opposing rotation of said pinion.

4. In a starting mechanism, the combine? tion with a gear wheel, and a pinion having pole pieces, of a shaft havlng a screwthreaded connection with said pinion, an electric motor operatively connected to the shaft, a pinion on said shaft having coact-- ing spiral threads, and means comprising an adjustable friction clutch for yieldingly 1 5 preventing relative movement between'said shaft and said motor except under predetermined conditions.

"6fIi1' "a starting mechanism, the combination an engine shaft, and a gear wheel I connected thereto, of a motor having a shaft,

a screw-threaded shaft, means comprising a friction clutch for connecting said screwthreaded shaft to said motor shaft and a pinionon said screw-threaded shaft for coacting with the gear wheel.

7 In a starting mechanism, the combination with an engine member, a motor and a shaft driven thereby, of a driving member movable longitudinally of said shaft and rotatable therewith to drive said engine member, and a friction clutch between said motor and said driving member.

8. In a starting mechanism, the combination with an engine member, a motor and a shaft driven thereby, of a driving member movable longitudinally of said shaft and rotatable therewith to drive said engine member, and a friction clutch between said 10. In a starting mechanism, the combinav tion with an engine member, a motor and a shaft driven thereby, of a driving member, means whereby relative movement between the motor and the driving member actuates said driving member into engagement with said engine member and a friction clutch between under 11. In a starting mechanism, the combinabetween said motor and said driving member for permitting relative movement thereredetermined conditions.

tion withan engine member, a motor and a shaft, of a pinion, carried by said shaft for longitudinalmovement thereon and rotary movement therewith, said ,pinion coacting with said member, and a friction clutch for operatively connecting said motor and said shaft, said clutch being so adjusted that it will transmit without yielding the torque necessary to rotate the engine under normal conditions, but will yield when the torque applied to the engine exceeds a predeter mined value.

12. In a starting mechanism, the combination with an engine member, a motor and a shaft, of a pinion carried by said shaft for longitudinal movement thereon and rotary movement therewith, said pinion coacting with said member, and a friction clutch for operatively connecting said motor and said shaft, said clutch being so adjusted that it will yield when the torque applied thereto exceeds a predetermined value and, when yielding, will transmit a torque greater than that required under normal conditions, whereby it will cease to yield when normal conditions are restored.

In testimony whereof, I have hereunto subscribed my name this 19th day of Dec. 1913.

Witnesses:

F H. PA'rrnN, B. B. HINES..

FRANK CONRAD. 

